This invention relates to a liquid-level detecting device especially for lubricating oil in an engine of an automobile.
The level of the lubricating oil of the engine in operation in which the oil is pressurized and distributed to various parts of the engine is different from that of the engine standing still in which all the oil return to an oil pan. When the engine is started, the oil level gradually decreases from the level L0 which indicates original level before the engine is started to the level L1 which indicates the level in the stable operation as shown in FIG. 1. However, since the oil temperature is generally low at the starting and the oil has relatively high viscosity, the distributed oil can not readily return to the oil pan, resulting in temporary decrease of the level below the aforementioned level L1, thereby causing a misindication of the oil level as for as the conventional detecting devices which are designed to alarm when the level has decreased below the level L1 are utilized.